Author Topic: Which carb should I build  (Read 2233 times)

Offline Corey

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Which carb should I build
« on: March 22, 2018, 07:55:42 PM »
I currently have 3 quadrajets to work with, the one on my car is 17059216 plus I have a 17085001 and a 17080282.   I have not found any reference material for these carbs may originally come from and have yet to strip any of them down to see what's inside.   I do know my car and one spare has CH secondary rods and the other spare has DR secondary rods. All three secondary hangers are different.

What I'm trying to decide is if I should tear down the carb I have on my car or go through one of the spares I have. I do have Cliffs book on rebuilding quadrajets I have been reading.

Car is a '78 Malibu. Bought it with 350 with edelbrock performer rpm qjet intake, currently has 333882 76cc smog heads on it, unknown cam but it's very lumpy idle.  TH350 trans, stock tall highway gears.

Offline qjetsrule

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Re: Which carb should I build
« Reply #1 on: March 23, 2018, 02:38:12 AM »
Corey, if I need a carb reference I'll just google the number and add quadrajet after it. I don't think the best quadrajet will help with a bad combination. I'd ask Cliff for a camshaft  recommendation to get the best performance out of your combination. It will save tons of grief and wasted money. Good luck with your Malibu.

Offline Cliff Ruggles

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Re: Which carb should I build
« Reply #2 on: March 23, 2018, 03:05:50 AM »
All three of those are nice units so I'd use the one in the best overall condition.

882 heads on a 350 SBC is going to be pretty low compression, even with flat top pistons. 882's also flow poorly so there isn't a lot of power waiting for you, even with a well chosen cam, intake, and exhaust.

They still work OK, but 882's showed up in 1974 and were used for many years on 350 SBC engines.  Those were the lowest power output and consumed the most fuel of any 350 made before or after.

I'd put some better heads on my wish list for sure. 

Without knowing the exact cam being used I'd get a vacuum reading at 700-750rpms with the initial timing around 12-14 degrees.  That will tell me what the idle system would require. 

I'd recommend having us set you up with a rebuild kit with tuning parts, to take the guesswork out of the equation.  I do this all the time and don't mind helping out if folks are throwing us a bone.......Cliff

Offline Corey

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Re: Which carb should I build
« Reply #3 on: March 23, 2018, 04:44:22 PM »
Currently just looking for info if one of these was better then the other, I found info on the 17059216, tells me originally on 305 or 350, but not the other two. Recently purchased the car as a project I could drive this summer and play with and do larger work during the winter, $500 was hard to pass on. And larger work is going to be this car getting stripped for parts to put in another shell that's not rusted out.    Plan is to watch this summer for a good deal on better heads and then next winter when I'm not driving the car I'll pull the heads and cam out to check pistons and cam see what I have.
 
I have carb kit I bought for gaskets while investigating why the secondaries weren't opening much(they were hitting the base gasket) before I found this website.   Think I shall start with dissecting the two carbs I'm not using currently to clean them and go through write down all the jet and drilled hole sizes before I go into the carb in the car now. 

Offline Cliff Ruggles

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Re: Which carb should I build
« Reply #4 on: March 24, 2018, 03:43:59 AM »
We're WAY past the day when you can find a "better deal" on good SBC cylinder heads. 882's are basically "door stops", and I don't care what you read anyplace on the NET they aren't worth putting one minute of you time or one cent of your hard earned cash into.  I've been building and dynoing SBC engines for decades and they will not make the grade anyplace.  The 624 counterparts to the 882's flow a little better, but the crack rate for them will be nearly 100 percent as they are paper thin and the factory got them too hot when induction hardening the seats IMHO.

The last of the good castings were 993's in 1973, and they had induction hardened seats so many of those will be cracked.  The good heads from 1970-72, 441's, 336's, 487's are "soft seat" other than a few very late 487X castings so they will need hardened exhaust seats installed for this new fuel.

The "holy grail" heads from the 1960's will lack accessory bolt holes, 291's, 461's, 462's, etc except for the excellent 041 and 186 castings from 1969 and 1970.  Even those are going to need hardened seats installed.

Also keep in mind that all the good early heads with few exceptions are pressed in studs and the valve guides will be worn some.

By the time you buy good factory castings, have a full set of good guides installed, machined for screw in studs/guide plates, hardened exhaust seats, good one piece valves, springs, retainers, locks, etc you could have bought a set of much better flowing heads with modern combustion chambers, much thicker material, hardened seats, one piece stainless valves, etc, etc, etc for less money.

My personal favorites are the World Products SR and Sportsman heads, but there are a LOT of companies in that market with similar products for even less money, and all of those heads are going to be superior to any factory head even after you are done spending a ton of money on them....FWIW......Cliff

Offline Corey

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Re: Which carb should I build
« Reply #5 on: March 24, 2018, 03:58:06 AM »
I remember my old boss talking about that with regards to refurbishing old heads vs just buying brand new ones with better flow then any factory head ever did. He always said the same thing by the time you go through a set of  "good" factory heads might as well buy new ones for the same or less money.   I have alot of learning to do, aside from a '00 durango with the 4.7 I've never owned a V8 anything other then economical commuter vehicles.  My only goals right now are keep it driveable as much as possible so I can have fun driving it this summer,  and whatever I do Eng wise I'd like to keep to low octane gas. I'm not going to the track, just cruising around

Offline Cliff Ruggles

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Re: Which carb should I build
« Reply #6 on: March 24, 2018, 04:36:05 PM »
Making great power is not a problem on low octane pump fuel.

Here is a clip of my daily driver at the track.  Then engine runs fine on any octane fuel I feel like putting in it.....Cliff

https://www.youtube.com/watch?v=6zVdoLR-VzM

Offline Corey

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Re: Which carb should I build
« Reply #7 on: April 14, 2018, 08:35:03 PM »
Pulled both the spare carbs apart to start cleaning then decided to pull look inside the 17059216 thats in the car check what jets/rods are in it and check condition.   Turns out it's the best condition and cleanest,  the other ones are going in zip lock backs and getting boxed up for later. 

17059216 has primary jets 75 and rods 41k  with CH secondary rods and G hanger.

I also have 43k and 50m primary rods and 2 sets 73 primary jets.   1 extra set CH secondary rods, one set DR rods. an O hanger and not sure if the other hanger is an I or L depending if it's upper or lower case it looks like just a line.   

Forgot in car description have a set of unknown shorty headers, dual 2 1/4 exhaust with glass packs no crossover.  with my tach working again I'm turning 3000 rpm at 110 km/h  with 215/70/15 rear tires so not as crap gears as I thought it would have.  Started reading what I can find on aftermarket aluminum heads but that won't likely be happening till next winter when the cars apart anyway.